The liver and brain are the most common sites of metastatic tumors. At the time of death, approximately two-thirds of patients with colorectal cancer have liver metastases. In addition approximately 83 percent of all brain cancers will be diagnosed as metastatic tumors. In this work, we propose to develop an improved laser thermal therapy system for treatment of cancer metastases. The BioTex Cooled Laser Delivery System will combine a novel cooled applicator and low power diode laser system. The proposed innovative applicator is designed to remove heat from both the fiber optic and tissue in contact with the applicator surface while maintaining a low profile and thereby causing less damage to normal tissue during placement. A reduction in temperature of the fiber optic applicator and surrounding tissue during laser irradiation will increase the overall light penetration into tissue, allow for longer exposure times, and produce larger photocoagulative lesions in a far safer manner than previously possible. Combining the novel applicator with a low-power diode laser that is reliable, convenient, and easy to use should greatly increase the overall appeal for laser therapy in the treatment of solid tumors. PROPOSED COMMERCIAL APPLICATION: This research is specifically targeted towards the development of a safer, more efficient minimally invasive treatment for metastatic tumors. Laser interstitial thermal therapy offers a unique opportunity for minimally invasive destruction of such tumors. A safer more efficient laser system would significantly increase the number of tumors amenable to laaser therapy and therefore result in a significant potential for commercial success.